Conventionally, four wheel floor conveyors, like counterweight stackers for instance, have two not suspended axles in order to ensure good stability. A suspending effect is mostly achieved only through the tyres, so that the driving smoothness and the driving behaviour are moderate, because the vehicle tends to jump.
From EP 1 162 092 A2, the entire contents of which is hereby incorporated by reference in its entirety, it is known to suspend the rear axle of a counterweight stacker in a suspended manner. From DE 1 580 793, the entire contents of which is hereby incorporated by reference in its entirety, it has become known for off-road vehicles and special vehicles for the transportation of heavy and bulky goods to support the front axle as well as the rear axle of the vehicle or the wheels belonging thereto, respectively, via double acting hydraulic cylinders which on their turn co-operate with hydraulic accumulators. In this context, it has further become known to couple the cylinder chambers of the hydraulic cylinders crosswise and to close the connection to the hydraulic accumulators in a voluntary manner if required. Because of the quickly changing axle loads and the turnover stability which is therefore required, this known arrangement can not be applied just like that to floor conveyors.
From DE 1 051 196 A1, the entire contents of which is hereby incorporated by reference in its entirety, it has become known for floor conveyors to swing the frame around the front axle with the aid of hydraulic cylinders, in order to tilt a lifting scaffold on which a load fork is height-adjustably guided about a predetermined amount in this way.
The present invention is based on the objective to provide a four wheel chassis for a floor conveyor, a counterweight stacker in particular, in which a high suspension smoothness is possible at all the wheels, without that the stability at lifted load is restricted. Furthermore, pitching movements of the vehicle body when taking up and setting down a load are to be avoided in a large extent.